//package leetcode;
//
//import java.util.ArrayList;
//import java.util.List;
//
//class Solution {
//    public List<Integer> spiralOrder(int[][] matrix) {
//        List<Integer> order = new ArrayList<Integer>();
//        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
//            return order;
//        }
//        int rows = matrix.length, columns = matrix[0].length;
//        boolean[][] visited = new boolean[rows][columns];
//        int total = rows * columns;
//        int row = 0, column = 0;
//        int[][] directions = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
//        int directionIndex = 0;
//        for (int i = 0; i < total; i++) {
//            order.add(matrix[row][column]);
//            visited[row][column] = true;
//            int nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];
//            if (nextRow < 0 || nextRow >= rows || nextColumn < 0 || nextColumn >= columns || visited[nextRow][nextColumn]) {
//                directionIndex = (directionIndex + 1) % 4;
//            }
//            row += directions[directionIndex][0];
//            column += directions[directionIndex][1];
//        }
//        return order;
//    }
//}
//
//public class Test2 {
//}
